Regiocontrolled Cu(I)-catalyzed borylation of propargylic-functionalized internal alkynes.
| Autor: | Moure AL; Departamento de Química Orgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain., Gómez Arrayás R, Cárdenas DJ, Alonso I, Carretero JC |
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| Jazyk: | angličtina |
| Zdroj: | Journal of the American Chemical Society [J Am Chem Soc] 2012 May 02; Vol. 134 (17), pp. 7219-22. Date of Electronic Publication: 2012 Apr 18. |
| DOI: | 10.1021/ja300627s |
| Abstrakt: | Good to excellent reactivity and regiocontrol have been achieved in the Cu(I)-catalyzed borylation of dialkyl internal alkynes with bis(pinacolato)diboron. The presence of a propargylic polar group (OH, OR, SAr, SO(2)Ar, or NHTs), in combination with PCy(3) as ligand, allowed maximizing the reactivity and site-selectivity (β to the propargylic function). DFT calculations suggest a subtle orbitalic influence from the propargylic group, matched with ligand and substrate size effects, as key factors involved in the high β-selectivity. The vinylboronates allowed the stereoselective synthesis of trisubstituted olefins, while allylic substitution of the SO(2)Py group without affecting the boronate group provided access to formal hydroboration products of unbiased dialkylalkynes. (© 2012 American Chemical Society) |
| Databáze: | MEDLINE |
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